Final answer:
Calcium (Ca) is the element from the given list most likely to form 2+ ions, correlating with its position in the second group of the periodic table.
Step-by-step explanation:
Element Ca (calcium) is most likely to form ions with a 2+ charge. This prediction is based on calcium's position within the second group of the periodic table, which contains the alkaline earth metals known for forming ions with a 2+ charge as they lose two electrons to achieve a stable electron configuration similar to that of a noble gas. Group 2 elements like calcium tend to follow this pattern, resulting in a cation with the same number of electrons as the nearest noble gas, which in the case of calcium, is argon.
Based on the periodic table, the element most likely to form ions with a 2+ charge is Ca (calcium).